1. Field of the Invention
The present invention relates to a technical field of diagnosing a damage condition of a gas turbine.
2. Prior Art
As an electric power generating facility and/or a heat supplying facility using a gas turbine, a gas turbine electric power generating plant, a combined electric power generating plant and a cogeneration plant are known. In the combined power plant, electric power is generated by combining a gas turbine and a steam turbine. On the other hand, in the cogeneration plant, electric power is generated by a gas turbine, and heat to be used for making hot water and heating rooms is produced by operation of the gas turbine.
The total equipment and the total number of components used in the plant reaches several tens of thousands. The equipment and the components composing the plant deteriorate with time so as to be in danger of causing a failure of the plant. Therefore, in order to stably supply electric power and heat by maintaining integrity of the plant, maintenance after occurrence of a failure in the equipment or the components composing the plant, that is, ex post facto maintenance, is sometimes performed.
However, preventive maintenance by scheduled inspection and repairs as a precaution is preferable if present operating conditions and failure conditions of the equipment and components composing the plant are known and their remaining lifetimes can be estimated.
As to prior art examples with respect to the preventive maintenance, the following technologies exist.
In a technology disclosed in Japanese Laid-Open Patent Application No. 2-294525, temperatures, stresses, strains and strain energies of high temperature component parts are estimated from values of operating conditions of a turbine, and then an amount of damage are checked every operation using operation data such as operating time, number of startup-and-shutdown times and so on. However, in the above prior art example, only the “cracks” are taken into consideration as the damage. In addition, the load change during normal operation is not taken into consideration.
In a technology disclosed in Japanese Laid-Open Patent Application No. 10-196403, an equivalent operating time for each of the components/parts, taking into account the operating time or the number of startup-and-shutdown times, the operating load condition and so on, is calculated by inputting present conditions and plant experience data stored in a unit provided in the plant, and the amount of damage is checked using the equivalent operating time. However, in this prior art example, the equivalent operating time can not be calculated until a start-and-stop operation is completed, that is, the equivalent operating time is not calculated in real time. Therefore, the effect of load change during the normal operation can not be taken into consideration, and further the damage and lifetime diagnosis can not be performed during operation in real time.
In a technology disclosed in Japanese Laid-Open Patent Application No. 10-293049, degradation and damage conditions of the gas turbine component parts after inspection such as scheduled inspection are predicted by inspecting the degradation and damage conditions of the gas turbine every inspection using practical degradation and damage inspection equipment and evaluating the degradation and damage condition using remaining lifetime diagnosing equipment. Therefore, in this prior art, the degradation and damage diagnosis is not performed either in real time during operation or after completion of each operation because the degradation and damage states are inspected every inspection.
In a technology disclosed in Japanese Laid-Open Patent Application No. 11-3113, degradation of a plurality of equipment units is efficiently diagnosed and managed by performing the diagnosis of equipment from a remote site. In the prior art example, there is no specific suggestion with respect to the method of diagnosing the degradation of equipments.
In a technology disclosed in Japanese Laid-Open Patent Application No. 7-65081, replacing timing of a component part and management of the replacing timing are performed based on consecutive hours using the component part. However, although the replacing timing in this prior art example is determined based on the consecutive using hours, an actual lifetime of component part can not generally be expressed only by the consecutive using hours, but the actual lifetime of component part can be accurately expressed when number of startup-and-shutdown times is also taken into consideration.
In a technology disclosed in Japanese Laid-Open Patent Application No. 8-44421, management of damage amount is performed based on cracks which are postulated to be mainly dominated by a number of startup-and-shutdown times, and maintenance and management support of the equipment is performed using a means for measuring degradation and damage amount of structural members, a means for recording operation history, a means for managing data and so on. However, since the degradation diagnosis predicting progress of damage is performed by calculation based on an estimated operating condition, the progressing condition of damage corresponding to the actual condition during operation is not known. Therefore, there is possibility that the actual condition of lifetime of the component part can not accurately be expressed.